2003 Strategic Environmental Assessment SEA4 Technical report - Seafloor sediments and sediment processes on the outer continental shelf, continental slope and basin floor (north UKCS)
This report is a contribution to the Strategic Environmental Assessment (SEA4) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). The report describes the surficial sediments in the SEA4 area and the sedimentary processes that are active in the area at the present day. The report focuses on the deeper water areas from the outer continental shelf to the floor of the Norwegian Basin in the northernmost part of SEA4. The report is based on sidescan sonar images, multibeam bathymetry, sub-bottom profiles, seabed photographs and sediment samples. The Holocene and late glacial events and processes that contributed to the present day seafloor morphology and sediment distribution are reviewed, as is the present day oceanographic regime. It is concluded that the present day sedimentary environment, seaward of the continental shelf edge at about 200 m water depth, is dominated by low sediment input and deposition rates, and by reworking of surficial sediments by bottom currents. The large scale seabed morphology was shaped mainly during the last glacial, when high sediment input resulted in glacigenic debris fan formation.
dataset
Strategic Environmental Assessment (SEA) data portal
- The Strategic Environmental Assessment (SEA) data portal provides free access to available data and reports which have been produced through the UK Department of Energy and Climate Change SEA process. The site is run and managed by BGS on behalf of the Department of Energy and Climate Change (DECC). Many files can be downloaded directly from this website. Those that are too large to download can be ordered via the website for postal delivery from BGS.
British Geological Survey
:
BGS_SEA_49
English
Environment
Geoscientific information
Oceans
Geoscientific information
Oceans
SeaDataNet Parameter Discovery Vocabulary:
GEMET - INSPIRE themes, version 1.0:
SeaVoX Vertical Co-ordinate Coverages:
Geology
Free:
-7.00,
58.70,
2.00,
64.00
publication: 2003-01-01
1996-01-01
-
2002-01-01
British Geological Survey (BGS)
Paul Henni
Murchison House, West Mains Road,
Edinburgh,
EH9 3LA,
UK
tel: +44 (0)131 667 1000
email:
offshoredata@bgs.ac.uk
Role: custodian
Department for Energy and Climate Change (DECC)
Admiralty Way,
London,
SW1A 2HD,
UK
tel: +44 0300 060 4000
email:
enquiries@decc.gsi.gov.uk
Role: originator
Data Quality
This report was prepared by Dr D G Masson and colleagues from the Southampton Oceanography Centre as part of the UK Department of Energy and Climate Change's Offshore Energy Strategic Environmental Assessment programme. Survey data used in this report includes sidescan sonar images, multibeam bathymetry, subbottom profiles, seabed photographs and sediment samples. This data was collected during a number of surveys funded by the Atlantic Frontier Environmental Network (AFEN) in 1996 and 1998 and by the DTI in 1999, 2000 and 2002. Sidescan sonar data was collected using two systems, the 30 kHz TOBI system in water depths greater than 200 m and a 100 kHz ORE or Widescan system at depths shallower than 200 m. The TOBI instrument package included 30 kHz sidescan sonar, 7.5 kHz profiler, three axis fluxgate magnetometer, CTD and an ultra-short baseline navigation transponder beacon. Sub-bottom profiles were collected using the 7.5 kHz profiler mounted on TOBI and a 3.5 kHz surface towed profiler. Seabed photography was carried out using the SOC WASP system, an off bottom towed camera. Three different sampling devices were used to cope with the wide range of surface sediment types, ranging from coarse gravel to mud, found in the SEA4 area. In fine grained sediments, a hydraulically damped multiple corer with up to twelve 10 cm internal diameter core tubes was used to obtain high quality cores up to 30 cm in length. In coarser sediments, particularly where significant quantities of gravel were present, this was replaced with a USNEL-type box corer capable of collecting a square section sample of 0.25"m2 and up to 50 cm in length. In very coarse sandy gravels, where other sampling devices failed, a Day grab was used as a last resort.
Minimal Distance:
5 http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/uom/gmxUom.xml#m
Constraints
Metadata about metadata
aba64100-c126-4de3-e044-0003ba6f30bd
British Geological Survey (BGS)
Mary Mowat
tel: +44 (0)131 667 1000
email:
offshoredata@bgs.ac.uk
Role: point of contact
2011-08-30